High-pressure water guns, as is known, terminate with a head comprising a mostly tubular main body and a rear portion to which an inlet connection is coupled, which connection exhibits an inlet conduit for a washing liquid. A nozzle for the liquid is housed internally of a front cavity in the main body.
Numerous types of head are known for high-pressure cleaning machines.
In some types, the nozzle is fixed internally of the main body and only a high-pressure directional jet is possible, or a fanned spray jet, having a variable angle of spread.
In other fixed-nozzle types, apart from the above functions, a low-pressure jet can also be obtained for aspiration of a detergent by means of an ejector installed in the water-cleaning machine.
Also known are rotating-nozzle heads provided with a mobile nozzle internally of the front cavity, which cavity is conformed and of adequate dimensions so as to be suitable for the motion of the nozzle.
The nozzle is located frontally and abuts an annular seating inserted in the front cavity of the main body, where it is made to rotate about itself internally of the annular seating and along a conical trajectory with vertices in the annular seating, by a jet of liquid which is oblique with respect to the longitudinal axis of the main body. The oblique jet is obtained by special means for conveying interpositioned between the inlet conduit and the front cavity of the main body. Thus a jet issues from the head which jet rotates with a trajectory similar to that of the nozzle head.
If other functions are required apart from the above-described rotating jet, for example a high-pressure directed jet and/or a low-pressure fanned spray jet, the prior art includes use of several interchangeable heads, each able to offer one or two functions, with obvious drawbacks relating to awkwardness and economy, or the use of heads each having three or four functions, where the flow is deviated into three or four different channels to supply different devices which are separate.
The prior-art heads exhibit numerous limitations and drawbacks.
Firstly, they are considerably unwieldy and complex from a constructional point of view. Production costs are therefore quite relevant.
Further, the prior art is sometimes poor from the point of view of performance, for example in terms of poor jet alignment with respect to the longitudinal axis of the heads.
U.S. Pat. No. 5,551,635 teaches a multi-function head for high-pressure water-cleaning machines which comprises an internal tubular body provided with an axial passage and an inlet for water. An external tubular body coaxially surrounds the internal body, is rotatable with respect to the internal body but axially fixed with respect thereto. A regulator element is mounted in the external body and is coupled to the internal body, so as to be axially mobile with respect to the internal body but fixed in rotary motion thereto. The axial motion of the regulation element with respect to the internal body is rendered by a cam which is solidly constrained to the external body. The head further comprises a front valve body connected to the regulation element, a rear valve body, axially aligned to the front valve body at a flat contact surface, and a rotating nozzle the front end of which is engaged in a frustoconical seating of the rear valve body. The front valve body, the rear valve body and the rotating nozzle are crossed by a conduit for water passage.
The rear end of the rotating nozzle is provided with an elastomer ring by means of which the rear end rolls in the axial passage of the internal body.
The axial passage is posteriorly delimited by a frustoconical guide provided with openings for inlet of the water flow, in which guide the rear end of the rotating nozzle can engage.
The front valve body, the rear valve body and the rotating nozzle are axially mobile in the internal body, by rotation of the external body and the motion of the regulating element. Further, the front valve body is axially mobile with respect to the rear valve body.
In a first operating condition, the front valve body is distanced from the rear valve body and the water passes through the conduit into the rotating nozzle and though passages surrounding the rear valve body. When the front valve body is moved towards the rear valve body, the two bodies enter into contact and the water can pass only through the conduit into the rotating nozzle. The rear end of the rotating nozzle is free to rotate in order to produce a rotating flow. If the front valve body is further displaced towards the frustoconical guide, the rear end of the rotating nozzle is confined within the guide itself and the diameter of the trajectory of the circular motion is progressively reduced. Finally, the rear end of the rotating nozzle is blocked in the base of the guide, preventing rotation in order to produce a fixed flow.
The applicant has found that this type of head too is susceptible to various improvements, in particular in relation to the performance provided and reliability over a length of time.
The technical aim at the base of the invention is to create a multi-function head for high-pressure water guns which obviates the above-cited drawbacks.
An important aim of the invention is to provide a multi-function head, comprising rotation of the nozzle, which is compact, light, constructionally simple and economic to make.
The technical aim is attained by a multi-function head which is characterised in that it comprises one or more of the solutions claimed in the appended claims.